Bag tray feed elevator mechanism for bag-loading machines



April 29, 1969 F PmN ET AL 3,440,801

BAG TRAY FEED ELEVATOR MECHANISM FOR BAG-LOADING MACHINES ofS FiledSept. 27, 1967 Sheet INVENTORS CLARENCE PRINCE P2150011 KAMLLA BY 61% qM we? S April 29, 1969 c PRlNCE ET AL 3,440,801

BAG TRAY FEED ELEVATOR MECHANISM FOR BAG-LOADING MACHINES Filed Sept.27, 1967 Sheet 8 of 3 INVENTOR5 CLARENCE AT PRINCLI 8 FRIEDOLF KAMILAApril 29, 1969 c PRlNCE ET AL 3,440,801

BAG TRAY FEED ELEVATOR MECHANISM FOR BAG-LOADING MACHINES Filed Sept.27, 1967 Sheet 3 of s .WVENTORD cLARNc F. PRINCE Pave: 001.; KAMILAUnited States Patent C 3,440,801 BAG TRAY FEED ELEVATOR MECHANISM FORBAG-LOADING MACHINES Clarence F. Prince, Springfield, and FriedolfKamila, Longmeadow, Mass., assignors to Package Machinery Company, EastLongmeadow, Mass., a corporation of Massachusetts Filed Sept. 27, 1967,Ser. No. 671,023 Int. Cl. B651) /02, 3/02, 43/26 US. Cl. 53-189 5 ClaimsABSTRACT OF THE DISCLOSURE sensing of a tray held bag supply by pivotedbag spreader elements.

Background This invention relates to bag-loading machines for preformedopen-ended bags of highly flexible thin sheet material or film, and moreparticularly to the elevator mechanism of such machines for accuratelypresenting a supply of empty bags in the form of stacked batches forcontinuous product-loading operations.

As will be recognized by those familiar with machines of the above typethe bags to be filled by such machinery are conventionally held instacked bundles on a wicket. The wicket is positioned on elevatingapparatus for raising the stack as article feeding mechanismsuccessively inserts products into the bags and strips the loaded bagsfrom the wicketed supply. The positioning of the wicket and elevatormechanism designed to raise the top bags of a stack to the properloading level for continued operation are of various types. Insofar asis known, prior elevator mechanism for holding wicketed bags and forproperly inserting a fresh supply while the machine is stopped is arelatively time consuming operation in order to properly arrange thestack and make the necessary adjustments to position it for continuationof the loading operation.

It an object of the present invention to provide a tray device andelevator mounting apparatus which will not only accommodate a wicket ofbags which way be readily set up and registered properly in the path oftravel of the load-ing operations, but also to provide for holding apreloaded tray of wicketed bags in reserve for the easily accomplishedrapid change over to a new supply whenever the bags of each wicket aredepleted. Accordingly, a minimum amount of interruption of machineloading operations is necessary.

Another object of this invent-ion is to provide a positive indexingmechanism for lighting the elevator as the supply of bags is graduallydepleted and to actuate this mechanism by utilizing the action of aknown type of spreader mechanism which is primarily designed to holdopen the mouth of the bag while the product is fed into the bag. In thisconnection lower spreader members when pivoted against the stack of bagsare used as a detector to sense the level of the bag supply and if belowan acceptable product loading level to cause the bags to be elevated byactuating a limit switch mechanism.

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In the present invention an elevator platform is disposed transverselyof the path of travel of the product in the machine loading channel. Theplatform is designed to carry two trays on each of which a wicket orstack of bags is prepositioned. One tray is releasably locked toregister the bags in the loading path. The other is held in reserve.When empty the platform is lowered and the registered tray is releasedand pushed onto storage rails as the reserve tray is moved intoregistered position. The platform is then raised and the tray is quicklyand automatically set into operative relation by the spreader detectoraction so as to resume loading.

The operation of the mechanism and additional specific objects andadvantages of the invention will be appreciated from the followingdescription of the embodiment thereof as shown by the accompanyingdrawings, in which,

'FIG. .1 is a front elevation in diagrammatic form of a bread baggingmachine in which the present invention may be incorporated;

FIG. 2 is a perspective view of the elevator frame and lifting apparatusand showing other portions of the machine to indicate a tray of bagspositioned in operative position on the platform for loading operations;

FIG. 3 is a side elevation of the elevator mechanism shown by FIG. 2,the platform being in its lower position;

FIG. 4 is a front end view of the apparatus shown by FIG. 3;

FIG. 5 is a perspective view of a tray unit;

FIG. 6 is a detail view showing a switch actuator assembly forautomatically operating the lifting mechanism; and

FIG. 7 is a schematic drawing showing mechanism for actuating the bagspreader elements and indicating the use thereof for sensing the levelof the empty bags and operating the switch mechanism of FIG. 6.

In FIG. 1 a bag loading machine is diagrammatically illustrated as anexample of the type of machine in which the apparatus of the presentinvention may be incorporated. The machine shown is adapted for baggingproducts such as bread loaves. Indicated at 2 is an infeed station onwhich a loaf of bread 4 may be deposited by suitable conveyor mechanism(not shown). A continuously moving endless conveyor at 6 has spacedpusher paddle assemblies 8 which are adapted to push the loaves 4 fromthe infeed station along a loading channel or path of travel to aloading station at 10. At station 10 a bag 12 is shown as receiving aloaf 4 through the open mouth of the bag. The mouth of the bag is firstblown open as by means of an air jet indicated at 14. Spreader elementsof a known type (not shown in FIG. 1) may then be inserted into themouth and hold it open for loading the bag. From the position of loaf 4at station 10 the loaf is advanced against the closed bag end and thusstrips the bag from the top of a wicketed stack of bags. The loaded bagis then carried across a platform at 16 in the loading path of traveland to a discharge station generally indicated at 18. The pusher at thispoint is withdrawn from contact with the loaf and carried back to theinlet end of the path. At station 18 the loaded bag may be picked up byconveyor apparatus (not shown) and advanced through known mechanism forclosing and tying off the mouth of the bag. This type of bag loadingmachine is known in the art and it will also be recognized that thereare also other bag-loading machines of the type wherein a reciprocablepusher inserts the products into the bags and advances the loaded bagsto a suitable discharge station for typing operation.

In FIG. 1 is also shown a control panel at 20 with push buttons mountedat the front of a housing 22 which encloses the framework and drivingmechanism for varions parts of the machine. Also supported by theframework of housing 22 is the elevator platform and mechanism of thepresent invention. The elevator mechanism and tray carriage is indicatedgenerally by numeral 24. Briefly the apparatus is designed to providefor releasably holding one active tray of bags on the lifting platformin a position of registration with the loading path for products to befed into the bags, and a second standby tray preloaded with bags and ina position to be quickly moved into the registered position once thesupply of the first tray is depleted. The platform holding the two traysextends transversely of the loading path of travel and may be consideredas being divided into two sections. One section is vertically offsetdirectly below said path of travel and the other section is laterallythereof. The latter section extends outwardly at the front of themachine as in FIG. 1. On said front section the reserve or standby trayis mounted. When the active tray is empty, machine operation stopsautomatically. The operator then lowers the platform, releases the emptyused tray, and immediately moves the reserve tray into registeredposition which pushes the empty tray onto storage rails at the back ofthe machine. Once the reserve tray is registered" the operator quicklyraises the platform and tray into operative loading position. Thebagging operations may then be continued. A further preloaded tray canthen be mounted in standby position on the front platform section forthe next changeover. Empty trays pushed onto the storage rails canaccumulate and be removed as desired for preloading with bags and lateruse.

The platform and tray carriage 24 is shown in detail in FIGS. 2, 3, and4. A bag table or platform support (FIG. 2) is conveniently in the formof a casting generally designated at and comprising a mounting plate 32affixed at the front of housing 22 (see FIGS. 1, 3, 4) from whichextends a vertically disposed and forwardly directed frame 34 having anupper flanged portion 36 and lower flanged portion 38. Centrally offrame 34 is provided a vertical enlarged portion 40 forming a bore forsupport of an elevator lift shaft 42 as will be more particularlydescribed. At the outer end of the frame 34 is a flanged end face 44 onwhich is supported ratchet mechanism for actuating the elevator liftshaft. The flanged face 44 (see FIG. 4) is provided with frameextensions 46 and 48 at each side thereof.

Referring now to FIGS. 2 and 3 a ratchet shaft 50 is supported at itsouter end in the extension 48. A handle operated turning wheel 51 isfixed on the end of the shaft. At its other end adjacent the portion 40the shaft is mounted in a supporting bracket member at 52. Outwardly ofextension 48 shaft 50 carries a ratchet wheel 54 and at its other endadjacent bracket 52 a pinion gear 56 pinned by collar 58 to shaft 50.Gear 56 is in mesh with teeth 60 of a rack formed on elevator lift shaft42, the casing 40 of shaft 42 being formed with side opening 62. Asshown by FIGS. 2 and 3, the upper end of the lift shaft 42 extendsupwardly of the frame flange 36 and is secured to a bag table slideblock 64 as by a set screw bolt at 65 in a depending boss of the block.Below the lower frame flange 38, shaft 42 is provided at its lower endwith a mounting strap 68 fixed thereto by screw bolt 70. Strap 68extends to one side of frame 30 and fixed to the strip is the outer endof a plunger 72 of a vertically positioned air cylinder 74. Cylinder 74is mounted on a plate 76 projecting from and fixed to the underside offlange 38. Cylinder 74 is a dampener to cushion the drop of the elevatortable as will be later described.

Fixed at the outer end of shaft 50 adjacent ratchet wheel 54 is aratchet actuator arm 80. Pivotally mounted at the end of arm 80 is thehead 82 of a plunger 84 of an air cylinder 86. Cylinder 86 is mounted(FIG. 4) on the end of a mounting plate 88 which is fixed by screw bolts90 to and angled downwardly from the lower end of flange 44.

Pivotally carried on arm 80 on mounting pin 92 is a lift pawl 94, thenose of the pawl (FIG. 4) being held against the teeth of the ratchetwheel 54 by a spring 96. One end of spring 96 is pinned to the end ofpawl 94, the other end being pinned to the end of a pawl detent plate98. Plate 98 is pivoted as at 100 on frame extension 46. The upper edgeof detent plate 98 bears against the lower edge of a stop pawl 102pivoted on frame extension 46 for urging the nose of the stop pawl toengage the teeth of the ratchet wheel 54. Fixed to pawl 102 is the stemof a hand release knob 103.

As will be apparent, particularly from FIG. 4, retraction of plunger 84by action of the piston of cylinder 86 will rotate ratchet 54 (clockwiseas in FIG. 4) by one notch and thereby drive pinion gear 56 to raiselift shaft 42 and the bag table support structure for the elevatorplatform which will now be described.

The table slide support 64 mounted on lift shaft 42 extends outwardlyfrom a position over mounting plate 32 to hang beyond the end of theupper flange 36 of the frame 30. As seen in FIGS. 2 and 3 an upwardlyoffset extension 104 is provided at its outer edge with an open endedslot 106 to receive a depending guide post 108 fixed in the underside ofsupport 64.

Support 64 (FIGS. 2 and 4) is flanged at the top and fitted withlongitudinally spaced fastener bolt assemblies as at 110 for securing tothe upper surface thereof a slide plate 112. Slide plate 112 overhangsthe top of slide support 64 and is provided with depending skirts at 114and 116. To the overhang having the shorter skirt 114 is secured, as byscrew bolts 118, an elongated slide block 120. To the overhang havingskirt 116 is secured an elongated strip member 122 fixed as by screwbolts at 124. The outer edge portion of the strip 122 overhangs theslide plate 112. The slide block 120 and strip 122 extend from one endof the support 64 to the other and provide tracking means for slidablyreceiving tray units each adapted to contain a stacked supply of emptybags preferably held by a wicket as will be described.

The assembly of the bag tray unit is best shown by FIG. 5. A bottompanel is provided as at with opposed side panels 132 and a dependingfront lip 134. Against the upper portions of the outer faces of sidepanels 132 are fixed, as by spot welding, a pair of tray side supportmembers 136. Support members 136 are outwardly offset from panel 132along the lower portions and form a channel between these portions asindicated by the arrows 138. The lower edges of supports 136 extendbelow the underside of bottom panel 130. The forward portions of theseedges are welded to the upper surface of a right angled front support140. The front lip 134 of the bottom panel 130 is also fixed as bywelding along the upper edge of the front face of the depending portionof angled support 140. The rearward underedge portions of the traysupport plates 136 are welded at a right angled rear support 142. Itwill thus be seen that the spaced relation of the front and rear angledsupports 140, 142 from the bottom panel 130 and the attachment of thefront lip 134 affords clearance for a sliding fit of a tray extensionplate 144 between said angled supports 140, 142 and bottom 130. The trayextension also has upstanding side guides 146 at each edge whichslidably fit in channels 138 between support members 136 and tray sidepanels 132.

The extension is also provided with elongated slots 148 in which arereceived short studs 150 fixed as by welding to the underside of thetray bottom 130 and provided at their outer edges by wing nuts 152.Accordingly, the extension can be secured in any adjusted position andthus be set for supporting various lengths of bags on the tray.

Referring to the angled front support it will be noted that along therear face thereof and fixed thereto as by welding is an angled guidemember 154 providing a lip in spaced relation to the underside of thehorizontal portion of the support 140. As will be seen from FIG. 4

guide 154 holds the edge of strip 122 between it and support 140 forsliding movement.

Also fixed to the depending front skirt of the support 140 at the frontside thereof is a bag wicket channel assembly. Referring to FIGS. 4 and5, this assembly comprises a pair of vertically spaced holding bars 156fixed to the front face of the vertical portion of support 140. Bars 156carry a pair of laterally spaced holders 160 in which the legs 162 of awicket may be inserted. The legs of the wicket are connected by acrosspiece 163. As will be readily recognized in the art the legs of the'wicket pass through spaced perforations in the lower edge extensions orlips at the open ends of the bags. The opposite edges at 166 of theupper wall portions are offset therefrom. As each bag is loaded it isstripped from the wicket. The sockets for receiving the legs of thewicket are at 168 (FIG. 5).

As best seen in FIGS 2 and 4, a tray unit loaded with a wicket of emptybags is placed on the tracks of the bag table slide at the outer endthereof so that the outer edge of the strip member is received as a gibbetween the horizontal lip of the front guide 154 and front angledsupport 140. The angled rear support 142 is positioned over the edge ofslide block 120. When so placed the tray may be slidably moved to aposition underneath the loading path or channel of the machine asindicated in FIG. 2.

Exact registration of a tray on the platform with respect to the loadingpath may be made by registering an opening 170 in the horizontal portionof the angled front support 140 with a releasable holding means (seealso FIG. 3). Opening 170 is adapted to be engaged by the tip end of aplunger 172 of a solenoid 174. Solenoid 174 (see FIG. 4) is mounted on abracket 176 aflixed as by welding to the inner face of the skirt 116 ofthe slide plate 112. The plunger 172 extends upwardly through an openingin the slide plate 112 and adjacent its upper end is fitted with a disk178. A spring 180 between the disk 178 and surface of plate 112 urgesthe disk and plunger upwardly. The edge of strip 122 is notched at 171to accommodate the spring and disk. The tip of plunger 172 will thusspring into opening 170 whenever the tray is moved into position. Byenergizing solenoid 174 the tip may be retracted to permit removal of atray from this registered position.

The position of the tray and stack of bags on the elevator platform asregistered for bag-loading operations will be appreciated from FIG. 2.The loading path of a bread loaf as previously described in connectionwith FIG. 1, is from infeed platform at 2 through bag spreader mechanismand into the open mouth of the top bag which is then Stripped or tornfrom the wicket and advanced onto platform 16.

Indicated in FIG. 2 between infeed platform 2 and the tray are portionsof the spreader elements, here shown as upper and lower funnel-likemembers, for holding the mouth of the bag open while a loaf is beingpushed into the bag. Also a bag sensor plate is shown at 200 over whichthe loaf is advanced from platform 2. Plate 200 is anchored in a fixedposition, its downstream end resting on cross bar 163 of the wicket. Oneach side of the plate 200 are indicated a pair of upper spreaderelements 204 and a pair of lower spreader elements 206. When the upperedge of the mouth of the top bag is blown open as by air jet 14 (FIG.1), the spreaders are adapted to extend into the mouth and are spreadapart to hold it open as the loaf is inserted by the pusher 8. Thisparticular spreader action is known in the art and various mechanismsmay be employed to accomplish such hold open action. In the embodimentshown the lower funnel-like spreaders are used in connection with thesensor plate 200 to maintain the top of the stack of bags at the feedinglevel of the product.

Referring now to FIG. 6 a limit switch mechanism is shown at theunderside of plate 200. This mechanism is mounted on a pivot block 208fastened to the underside of plate 200. A pivot pin is at 212 in a yokedportion 210 of the block. On pin 212 is pivoted the ends of a pair offorked arms of a switch mounting member 211, one such arm being shown at214. A switch at 216 is mounted between the arms and at the outer end ofmember 211 is an extension 218 receiving in an aperture thereof the stemof a depending screw bolt 220 fixed in plate 200. A nut 222 on the endof bolt 220 holds the switch arm in an adjustable lower position, aspring 224 surrounding bolt 220 urging the arm against the nut. Thespring is seated at its other end against the underside of a switchactuating lever at 226 also apertured for passage of bolt 220.

Actuating lever 226 lies against the underside of plate 200 and is alsopivoted on pin 212 having a pivot block 228 rotatable on the pin betweenthe arms 214 of member 211. Lever 226 extends beyond the end of themounting member 211 and at its outer end is provided with a cross bar230 fixed thereto as by welding on a flatted portion thereof. Bar 230extends laterally of each side of plate 200 and on each extension isfitted a tube 232 (see also FIG. 2). Against the underside of lever 226(FIG. 6) is a spring leaf trigger at 234 opposed to the button 236 ofthe switch. In the construction shown the switch mounting arm 211 andactuating lever 226 are y-ieldably held apart by spring 224 on bolt 220.It will be seen that when the bar 230 is moved downwardly by strikingthe tubed extensions, lever 226 will pivot on pin 212 against spring 224and thus cause trigger 234 to actuate the switch. The switch isconnected in circuit with a solenoid valve 240 for operation of cylinder86 (FIG. 4) of the elevator ratchet mechanism. Actuating the switchcauses cylinder 86 to operate arm and drive the wheel 54 to raise thetable and tray of bags.

The switch lever is operated by the lower funnel members to raise thelevel of a stack of empty bags in a tray whenever a sufficient number ofbags have been loaded and stripped to cause the top bag level to belowered below the feeding level along which the products are traveling.As will be noted from FIGS. 2 and 7 the cross bar 163 of the wicket isheld in a notch at the underside of the plate 200. Whenever the tray israised, the wicket is thus held stationary while the stacked bags arepushed upwardly by the tray to maintain the compactness of the remainingbags on the wicket for further loading operations.

The wicket holds the lip extensions only of the lower bag walls, as willbe appreciated, and thus the body of the bags is offset upwardly thereofat the level of the surface of the plate 200 (FIG. 7). It will befurther realized that the spreaders will be advanced in collapsedposition for the ends to project into the mouth of a bag opened by theair jet. The spreaders are then opened up to hold the bag mouth forentry of the product. Thus, as the lower spreaders are pivoted to swingdownwardly and lie in contact with the upper surface of the stack, thelimit of pivotal movement is determined by the stack level. If thislevel is at or near the level of plate 200 the spreaders will notcontact the switch lever tube extensions 232. If, however, the stack hasbeen depleted to the extent that the topmost bag is suflicient lowerthan plate 200, the spreaders will strike the lever, actuate the switch,and cause the tray to be raised by the ratchet mechanism described. Themechanism for actuating the spreaders 204 and 206 and thus operating theswitch lever is schematically shown by FIG. 7.

In FIG. 7 the sensor plate 200 is indicated as fixed on frame mountedbrackets at 250. A single pair of funnellike spreader elements 204 and206 is shown carried on the post of a mounting bracket 252 and pivotedat 254 and 256 respectively. A shaft at 258 is rotatably mounted in thebracket and fixed on the shaft is a pivot arm 260. At the top of arm 260is pivoted a link 262 which is pivoted at its other end to the lower endof an actuating lever 264 fixed on the pivot of the upper spreader 204.A lower link 266 is also pivoted on pivot arm 260 and passes through astud-like piece 268 projecting upwardly from the lower spreader 206above pivot 256.

Pivot arm 260 is normally urged in the direction of the bracket post byspring action as schematically indicated by spring 270 fastened at itsends on the arm and post. It is held in the position shown as will belater described.

Bracket 252 is mounted on a spreader carriage, a side plate portionthereof being indicated at 272. A shaft 258 and a rod 274 passingthrough the bracket is supported in plate 272 and a similar plate at theother side of sensor plate 200. As indicated side plate 272 of thecarriage has a pair of rollers at 276 which are received in a recessedgroove indicated at 278 of a frame mounted guide support. The spreadercarriage is reciprocably movable to shuttle back and forth for each bagloading operation. Fixed to the underside of the carriage is a bracketto which is pivoted a link 280 carried on one arm 282 of a bell crankfulcrummed on a fixed shaft 283. The other arm of the crank is at 284, aface cam follower roll 286 being at the other end for movement of thecrank to advance and retract the spreader elements.

As previously stated the spreaders are advanced in collapsed position(as shown) into the open mouth of the bag. The spreaders are then openedup for entry of the product. The opening operation is spring operated.In FIG. 7 on the outboard side of side plate 272 and fixed to pivotshaft 258 is an actuating lever 288 angularly related to pivot arm 260and carrying a roller at its outer end in contact with the upper edge ofan arm 290 of a funnel spreader bell crank lever. The other arm of thelever is at 292, the fulcrum being at 294. Arm 292 is also cam actuatedhaving follower 296 at its outer end. The arm 292 is moved as to theright when the collapsed spreaders are inserted into the bag. Thus, arm290 is lowered and lever 288 is released for the pivot arm 260 to springas to the right to open up the spreaders. The position of the lowerspreader on the stack of bags is indicated in phantom lines. It willreadily be seen that in the event the stack is at a lower level thespreader 206 will strike the switch actuator 232 to raise the level.

In operation when the elevator platform is raised to the level where thestack of empty bags is depleted the machine is stopped. This may beaccomplished by suitable switch mechanism as, for example, the bagdetecting finger or feeler switch unit at 11 located above the loadingstation 10 in FIG. 1. In the event no bag remains on the tray to beblown open by the air jet 14, the detector switch 11 operates to stopthe machine. Referring to FIG. 2 the platform is then lowered by turningknob 103, fixed to stop pawl 102, to release ratchet wheel 54. Theweight of the table slide support 64 and parts carried on it will lowerthe platform on lift shaft 42 very rapidly. In order to cushion thefall, plunger 72 of cylinder 74 is attached to the strap 68 fixed on thelower end of shaft 42 and acts as a dampener. In the lower position, seeFIG. 3, the empty tray may now be released by energizing solenoid 174 asby one of the push buttons of panel (FIG. 1). The plunger 172. thus isout of engagement with opening 170.

As soon as the empty tray is thus released the reserve tray with fullsupply of wicketed bags can be manually moved to push the empty trayonto the storage rails shown at 111 (FIG. 3). The tip of the lockingplunger 172 may remain depressed by holding the control button. When thenext tray is approximately registered the solenoid may be deenergizedand the operator may move the tray back and forth over the plunger untilopening 170 of the reserve tray comes into registration with theplunger. The snap of the plunger in the opening will indicate to theoperator by feel when the tray is properly registered. As soon as soregistered, the operator can then manually turn the lifting wheel 51 ofshaft 50 and raise the platform until the new tray engages the notch atthe underside of sensor plate 200 or nearly so. At this point thespreader mechanism as schematically shown in FIG. 7, may be operated asby another of the control panel push buttons and without feeding productthrough the spreaders. In this way lower funnel elements 206 will seekto detect the top level of the stack of bags. Until the proper level isreached the actuator switch will thus be actuated to operate the ratchetand lift the platform. When at the correct level the bagging operationscan be resumed and when convenient the operator may place anotherreserve preloaded tray with a full wicket of bags on the front sectionof the platform.

What is claimed is:

1. In elevating apparatus for bag-loading machines having means formaintaining the top of a stack of preformed open-ended empty bags at aloading level to suecessively receive products pushed along the plane ofa loading path into the open mouths of the bags and against the closedends thereof for advance to a discharge station and thereby strippingthe bags from said stack;

a platform movable between upper and lower levels, said platformextending transversely of said loading path in offset relationshiptherebelow and having a first portion directly underneath said loadingpath of travel and a second portion laterally thereof,

a tray having means for positioning a stack of empty bags thereon,

said tray and platform having interengageable members for guidedmovement of the tray from said second portion to said first portion ofthe platform and releasable locking means for holding said tray in aposition of registration and alignment with said loading path on saidfirst platform portion.

2. The structure of claim 1 in which said interengageable members of thetray and platform comprise tracking strips extending longitudinally ofsaid platform and angled supports on which said tray is carried slidablyinterfitting with said platform strips,

said locking means for said tray comprises an apertured portion in thebase of one of said angled tray supports and a solenoid operated plungermounted on said platform is engageable in said apertured portion, and

storage rails is aligned endwise relation to said platform at its lowerlevel are provided for receiving trays moved off said platform from saidregistered platform position.

3. The structure of claim 1 in which said tray is provided with a bottomand side walls, and

a bracket is mounted forwardly of and below the front edge of saidbottom wall and provided with vertically disposed spaced wicket-holdermembers having sockets for receiving the legs of a U-shaped wicket onwhich said stack of bags may be carried.

4. The structure of claim 1 in which are provided,

elevating means for incrementally raising said platform towards itsupper level,

means for detecting the upper level of the stack of bags on a trayduring each bag loading operation, and

means for sensing a condition wherein said upper level of bags is belowsaid loading level,

said sensing means including a switch with an actuating lever engageableby said detecting means, said switch operating said elevating means.

5. The structure of claim 4 in which said elevating means is a ratchetoperated lifting mechanism powered by solenoid operation,

the means for positioning a stack of bags on the tray includes a wicketand holder elements therefor positioned at the front of the tray,

said sensing means also includes a fixed plate defining the level oftravel of said products and the end thereof is engaged by the wicket ofa tray elevated in reg- 9 l0 istered position, the said switch beingpositioned References Cited under said plate and said actuating leverthereof is UNITED STATES PATENTS provided With arms extending laterally0f the plate,

and 2,108,613 2/ 1938 Rider.

said detecting means is provided by lower bag spreader 5 EDWARD A.SROKA, Primary Exam-"m elements carried at each side of said fixed plateand having means to move into the open mouth of a bag us 1 R and pivotto rest on the top of said stack of bags. 271-62

